Compact artificial transmission line



g- 12, 1952 N. E. LINDENBLAD 2,606,968

COMPACT ARTIFICIAL TRANSMISSION LINE Original Filed Sept. 24, 1'942 Fgl if 'INVENTOR. {$2. M

' wrember 21,1945, Serial No. 630,076

Patented Aug. 12, 1952 ooMPAc'r ARTIFICIAL TRANSMISSlQN Linn,"

Nils E. Lindenblad, Rocky Point, N. Y., assignor to Radio Corporation of America, a corporatio of, Delaware I I -"Original application September 24, 1942, Serial No. 459,457. Divided and this application No- Claims.

This application is a division of parent U. application Number 459,497, filed September 24, 1942, and issued on'A'pril 11, 1950, as U. S. Patent 2,503,955. g

The present invention relates to electrical cir cuits having characteristics" similar to those of transmission lines.

An object of the present invention is the provision of an artificial line having uniformly distributed characteristics.

Another object of the present invention is the provision'of an artificial line which is compact in size.

Still another object of the present invention to frequency.

of energy.

as a natural line.

a shield 32.

sive turns of the helix being slightly spaced one 2' from the other. The helix, after being removed from the mandrel is then space wound upon an insulating support 3| which may be a glass'tube or rod, The supportSl may be threaded to hold 1e turns in place orthey may be cemented to the support by coating them with shellac or other cement. the shields 32 are preferably welded or soldered together into a honeycomblike arrangement with combined spacing fins and supportinglegs 38 attached to the periphery to maintain the desired-relationship between the shields, the casing and the coils. V

The turns of the original helix, being of such small diameter, have very little self-inductance,

is the provision of an artificial line having charit d t e mutual ductance is also W While acteristics which do not vary with changes in e field O each turn about pp 3| is the frequency of energy applied thereto. stantially confined to its own volume. Thus the A further object of the present invention is the total length f Wire c S b ant a y a thou provision of an artificial line which has a phase it Were Stretfihed Ou at u l e h While S ill shift characteristic which is linear with respect 2 py a much m r mpact n iner.

While I have particularly shown and described Still a further object of the present invention a p r i r embodiment of h pr n inv nis the provision of a compact artificial line which, tiOIl, it ShOllld be Clearly de d a the in pite of t size, 111 hamue large amounts invention is not limited to this form alone, but

that modifications may be made. The foregoing objects, and others which may What is Claimed is! appear from the following detailed description, A Compact artificial e including an e10nare attained in accordance with the principles sated conductor, id elongated u or being of t present invention by so coiling or folding wound into a helix of small diameter, said helix a natural line t t t occupies n pacg being wound into a coil having an inner diameter t t t t same t introducing such substantially the same as the diameter of said mutual inductive effects, either electrostatic or helix, adjacent turns of d 00i1 be paced electromagnetic, between different convolutions apart y a distance at which t e fie d of each or layers of the coiled line that it ceases to act turn of Said Coil is Confined o s Own volume to prevent substantial decrease of mutual in- Th present i nti ill b more fully nd ductance, whereby the self inductance of the stood by reference to the following detailed de- 6011 is substantially greater than that of said scription, which is accompanied by a drawing in elongated conductor. which Figure 1 illustrates in vertical section an 2. A compact artificial line including an elonembodiment of the invention, while Figure 2 ilgated conductor, said elongated conductor being lustrates a transverse section of said embodiment. wound into a helix of small diameter, said helix Referring now to the drawing, the present inbeing Wound into a coil about a support having vention utilizes a plurality of separate line seca diameter substantially the same as the diamtions 10 each of which may be supported within eter of said helix, the helix being insulated The sections may be connected from said support, adjacent turns of said coil in series and placed Within a conductive conbeing spaced apart by a distance at which the tainer 34 which is filled with transformer oil. field 0f each t of Said 11 is confined to its The COIltaineI y be Covered by an insulating own volume to prevent substantial decrease of -35 which carries a terminal 36 to which 0 8 mutual inductance, whereby the self inductance end of the line is connected, the other end being of the coil is substantially greater than that of connected to the container 34 as indicated at said elongated conductor, and. a tubular shield- 40. Each line section II] is constructed by first ing member surrounding said coil. winding the conductor l2 upon a small diameter 3. A compact artificial line including a plumandrel to form an elongated helix, the succesrality of line assemblies each comprising an elongated conductor, said elongated conductor being wound into a helix of small diameter, said helix being wound into a coil having an inner diameter substantially the same as the diameter of said helix, adjacent turns of said coil being spaced apart by a distance at which the field of each turn of said coil is confined to its own volume to prevent substantial decrease of mutual inductance, whereby the self inductance of the coil is substantially greater than that of said elongated conductor, and a tubular shielding member surrounding said coil, said assemblies having the elongated conductors thereof connected in series and the shielding members thereof connected to a point of zero reference potential.

4. A compact artificial line including a plu rality of line assemblies, each comprising an elongated conductor, said elongated conductor being wound into a helix of small diameter, said helix being wound into a coil having an inner diameter substantially the same as the diameter of said helix, adjacent turns of said coil being spaced apart by a distance at which the field of each turn of said coil is confined to its own volume to prevent substantial decrease of mutual inductance, whereby the self inductance of the coil is substantially greater than that of said elongated conductor, and a tubular shielding member surrounding said coil, said assemblies having the elongated conductors thereof connected in series and immersed in an insulating fluid.

5. A compact artificial line including a plurality of line assemblies each comprising an elongated conductor, said elongated conductor being wound into a helix of small diameter, said helix being wound into a coil having an inner diameter substantially the same as the diameter of said helix, adjacent turns of said coil being spaced apart by a distance at which the field of each turn of said coil is confined to its own volume to prevent substantial decrease of mutual inductance, whereby the self inductance of the coil is substantially greater than that of said elongated conductor', and a tubular shielding member surrounding said coil, said assemblies having the elongated conductors thereof connected in seriesand the shielding members thereof connected to a point of zero reference potential, said assemblies being immersed in an insulating fluid.

NIL-S E. LINDENBLAD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,264,119 Neal Apr. 23, 1918 1,593,725 Sharpe July 27, 1926 1,718,255 Ranzini June 25, 1929 1,903,054 Laurent Mar. 28, 1933 

